Banaba (Lagerstroemia speciosa L)


By: Laura Shane McWhorter

Banaba is a variety of crepe myrtlethat grows in the Philippines, India,Malaysia and Australia. A tea made fromthe leaves is used to treat diabetes.

Active ingredients include corsolic acidand tannins, including lagerstroemin.These ingredients are thought tostimulate glucose uptake and haveinsulin-like activity. The latter activity isthought to be secondary to activationof the insulin receptor tyrosine kinase orthe inhibition of tyrosine phosphatase.

Banaba has been used for diabetesand weight loss, although informationregarding long-term human use is notavailable. No adverse effects have beenreported with its use.

Drug Interactions

Banaba may cause blood glucoseto be excessively lowered whencombined with drugs that can causehypoglycemia, such as sulfonylureas(glyburide or glipizide), or withcomplementary and alternativemedicines (CAM) that havehypoglycemic activity (Gymnemasylvestre, American ginseng, and thelike). Doses of these medications orCAM therapies may have to be adjustedto prevent excessive lowering of bloodglucose.

What is banaba, and can it help mydiabetes?

Banaba is a leaf extract from a crepemyrtle species found in the Philippinesand Southeast Asia. This product may helppromote glucose uptake and produceinsulin-like effects. It has been studiedin rodents, but a small study in patientswith type 2 diabetes found that a soft-gelformulation of the extract, called Glucosol(now called GlucoTrim), lowered glucose.

There are no serious side effects associatedwith the use of banaba, but hypoglycemiamay occur, and the patient’s dose ofdiabetes medications may have to belowered. There is limited informationregarding the use of this product, so it is notrecommended at this time.

A 15-day randomized control trial on banaba was done in 10patients with type 2 diabetes and fasting glucose levelsbetween 140 and 250 mg/dl. The results of the trial werepublished in a 2003 issue of the Journal of PharmacologicalSciences (93:69-73).

Diabetes medications were stopped 45 days before thestudy. Three different doses of banaba—16 mg, 32 mg, or48 mg—in either a soft-gel or hard-gel formulation wereused.

Five subjects in each group received the three differentdoses for 15 days, with a 10-day washout between doses.Basal glucose was determined by a fasting blood sampleseven days before starting banaba.

During the study, three samples were taken, and anaverage of the three readings was compared to the basalvalue. The 32- and 48-mg soft-gel formulations showed11 percent and 30 percent decreases, respectively, frombasal values after 15 days of treatment. Only the 48 mghard-gel formulation showed a significant decrease of 20percent, but it was still lower than the soft-gel formulation.

Some online sources for gel and tea formulations of banaba are



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